Huge difference in texture quality bw pbr-material-layering and pbr-metall-rough

[supermaximus]

Hi.

As I wrote in my previous reports, I play with fire hydrant spp file from substance share and try to convert it from layering shader to metallic/roughness.
Today I found a huge difference in texture quality between pbr-material-layering and pbr-metall-rough shaders.
The old pbr-material-layering shader displays material textures in viewport very good, highly detailed even in 2k resolution. Perfect.
However, pbr-metall-rough shader displays the same material textures too smooth and undetailed. Params are the same: 2k textures resolution and shader quality low. Even after I set textures resolution to 4k, pbr-metall-rough still displays textures a little bit worse. I guess the same quality could be achieved by setting 8k textures resolution. But, i don't have such possibility in SP.
So my question is.
Why there is so huge difference in quality between pbr-material-layering and pbr-metall-rough shaders?
Why the new one pbr-metall-rough quality is so worse, comparing to pbr-material-layering shader? It's the new one and it should look better, right. I can increase texture size to 4k to get comparable result, but in this case I will loose in performance and dramatically increase spp file size, which I don't want to do!
Is there a solution for this problem? Could it be somehow fixed?

I use SP 2019.2.3 on windows 10.

Thanks.

[Jeremie Noguer]

The material layering shader blends materials together in the shader and is not constrained by texture resolution or UV space, while the regular pbr metal-rough shader has to fit everything in the UV space, limiting the overall resolution to whatever the texture set is set to.

layered shaders are very specific to some game engines and usually require some custom shader work, the one in Substance Painter is just an example of how these types of things could work but isn't really usable as is.